Newbie with questions

Hey, I've been trying to figure out my deal with my medical issues, and pots seems to fit the bill (heat intolerance, headaches, dizziness when standing, hEDS joint instability). Recently I went to a cardiologist and he dismissed me out of hand and told me I was just fat (tbf I am fat). I've been trying to figure out treatment, but it looks like all the electrolyte stuff is no sugar. Correct me if I'm wrong, but you need sugar for cell water transport too, right? What electrolytes do I need?